Thursday, February 11, 2010

Peeling Paint, I've been told to get wall vents, any feedback?

I have bad peeling paint and was advised to add venting to the exterior of my house before painting to decrease the moisture inside the walls. My neighbor said the house never held paint and he's been there for 40 years. Does anyone know about these add on wall vents?Peeling Paint, I've been told to get wall vents, any feedback?
The wall vents may only be a temporary bandaid covering over the real source of the problem. It might not even provide any benefit at all. Putting a few in a particular area that is prone to some moisture condensation may be o.k. However, there are a lot of questions to answer before you decide to drill 2 inch holes in your walls every couple of feet around your house for those little wall vents.





You should research exterior painting techniques at some websites like This Old House and Old House Journal that deal with older houses.





If an entire wall is peeling, the siding may very well need better ventilation. One solution is to slip eighth-inch thick wedges under the lower edge of each siding board. Some paint companies sells plastic snap-off devices for this purpose. Do not caulk the bottom edge of the clapboards.





If it truly is a moisture problem then you should probably try to figure out where the moisture is coming from and fix that first before you spend a lot of money on a temporary paint job.





Often in older homes there is little or at least poor vapor barriers in the wall so in the winter it allows moisture to pass through the wall from the inside and condense on the back of the cold exterior siding where it then soaks through and loosens the paint. The little vents may give some relief to this condensation problem, but then in the summer they will let moist air get into the wall from the outside and condense on the back of the cold interior wall and lead to other problems.





Adding vapor barrier film under surface on the side of the wall that is heated most often can avoid the moisture from passing through the wall. This would mean applying it under the inside wallboard on the interior walls is recommended for homes in cold climates and putting the vapor barrier under the exterior siding is often the preference in homes in hot climates.





Moisture in your exterior walls can also be due to leaking or missing gutters that let rain water run down the wall and splash up on the wall that soaks into the siding. Then as it dries out the water vapor comes back out of the siding and lifts the paint. Poor attic insulation, ventilation and vapor barriers can lead to ice dams in colder climates that then let melting ice dump loads of water into the attic and down inside the exterior walls.





It may not even be a moisture problem. It could be as simple as someone painting latex paint over several layers of brittle old oil paint. Most experts recommending never switching from oil to latex, even thought modern latex paints are better than modern oil paints. If the old oil paint layer is in good shape then you might be o.k., but since yours sounds like it's not good then covering it with latex paint is asking for trouble.





Unfortunately, the best solution since your paint is already peeling so badly may be to either strip it down to bare wood or remove the old siding and apply new siding and then prime and paint the bare wood with a good quality all-acrylic latex paint. That is, once you make sure there's not a moisture problem that needs fixing first.





This is why so many people turn to vinyl siding, because it is cheaper than stripping and repainting. However, if you do have a moisture problem in the wall then the vinyl siding will make the situation worse by holding moisture againt the framing and resulting in rot a few years down the road.





I hope this helps, but you may want to interview some local, trusted paint contractors because without seeing it directly it's hard to say exactly what to do.

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